4 ms·

Auto is already taken in C. It’s the default, rather than register or static, so you hardly ever see it

• kazinator 8y ago
  auto was taken in exactly the same way in C++ until fairly recently. They re-purposed it because it was obsolescent. auto was already in vanishing disuse in C at the time ANSI C came out in 1989. The C++ use of auto resurrects an aspect of the way auto was used in the C predecessor languages B and NB. In these pre-C languages, everything was an integer cell. A declaration of local variables looked like this: auto x, y; the auto meant automatic storage (stack), but the real purpose here is syntactic: the auto is a declaration specifier, which makes the above construct a declaration. There is no indication of type, because it is implicit. Without the auto it would look like a comma expression with no effect. This implicit typing survived into C for "implicit int" return values, like "main () {...}". But type specifiers were introduced and became mandatory in declarations, and so auto became unnecessary verbiage since all it did now was specify a storage class that was already the default one. C++ resurrect the syntactic use of auto in a way: once again, it provides declaration syntax that allows the type specifier to be omitted. This time, of course, that type is inferred rather than assumed integer.
  • jfoutz 8y ago
    This is a great thoughtful reply to my terse, shallow comment. Thank you. It’s insightful